Effects of carbon fiber/Al interface on mechanical properties of carbon-fiber-reinforced aluminum-matrix composites

Carbon-fiber (CF)-reinforced aluminum-matrix composites were prepared by spreading fibers and squeeze casting. The interface structure of CP/AI composites was examined using high-resolution transmission electron microscopy (HRTEM) and electron spectroscopy for chemical analysis (ESCA). Aluminum carbide (Al^sub 4^C^sub 4^) interfacial reaction products were observed to nucleate heterogeneously from carbon fibers and to grow toward the aluminum matrix in the form of lath-like crystals after heat treatment. The growth of aluminum carbide was anisotropic, since it was faster along the a- and b-axes of the basal plane than along the c-axis. Both the tensile strength and the elongation of composites decline with an increased duration of heat treatment. The results of ESCA revealed that approximately 1 pct of carbide enhanced interface bonding. However, increasing the content of brittle carbides to over 3 pct after heat treatment degraded the mechanical properties of composites. [PUBLICATION ABSTRACT]